The zone goes by different names, few of them complimentary. Victor Hugo called it "bastard countryside". The landscape theorist Alan Berger called it "drosscape". The artist Philip Guston called it "crapola". And the environmentalist Marion Shoard called it "edgeland", which she defined as "the interfacial interzone between urban and rural". The edgelands are the debatable space where city and countryside fray into one another. They comprise jittery, jumbled, broken ground: brownfield sites and utilities infrastructure, crackling substations and pallet depots, transit hubs and sewage farms, scrub forests and sluggish canals, allotments and retail parks, slackened regulatory frameworks and guerilla ecologies.

For Paul Farley and Michael Symmons Roberts, these are the great "unnamed" and "ignored" landscapes of modern England: places where "our slipstream has created a zone of inattention" in which all manner of interest and beauty thrive. Two English poets "in the lyric tradition", both "edgelands comprehensive schoolchildren in the 1970s", they set out to explore and document this ruderal idyll, hoping to "do for the neglected edgelands what Coleridge and Wordsworth once did for mountains and lakes". Their co-written book instructs us to "marvel at this richly mysterious . . . region in our midst", and to celebrate it as a "place of possibility, mystery, beauty".

So off they wandered, to the brinks of mostly northern English cities, returning with their post-pastoral harvest of prose. The book takes the form of 28 essays, each treating a charismatic aspect of the edgelands – "Cars", "Canals", "Ruins", "Mines", "Hotels", "Sewage" – and each a spray-can squirt in the eyes of the National Trust. The authors' political aim is explicit and harped upon: to chastise the "routine prejudices" that we hold with regard to landscapes. Well, they succeed in that, but they also install replacement biases and nostalgias of their own.

At its best, this book is a delight: witty and wryly contrarian. Farley and Symmons Roberts have conjured a distinctive style for their chosen region: fond, melancholic and glitteringly acute. An exemplary incident comes when one night "on an industrial estate near Morecambe" they encounter an "Iridium Flare watcher": a man waiting, with binoculars, for the moment when a low-earth-orbit communications satellite will flash the sun from its silvery coachwork. They write brilliantly about this contemporary Halley "looking to the heavens to acknowledge the presence of our telecom gods", and the man himself becomes an icon of the book's preoccupations.

Their prose can be close to poetry: the "hum and rumble of skateboards", the "dark dials" of sewage ponds seen from above, the "imponded cars" that have sunk into the water of quarries and gravel pits. There are dozens of fascinating digressions as well as charming counter-factual flourishes in which imaginary futures for the edgelands are envisaged.

Of course, Farley and Symmons Roberts are not the first to venture into the edgelands, nor is the region nearly as ignored as they suggest. For decades the edgelands have been crawling with chroniclers: psychogeographers, biopsychogeographers, autobiopsychogeographers, deep topographers, and other theoretically constituted lovers of the detrital, gleaning their ruminations on ruination. The edgelands are all over late-20th-century English painting, photography, film (Patrick Keiller, Chris Petit, Andrew Kötting, who has even made a short called Edgeland Mutter), in children's literature (Stig of the Dump, The Turbulent Term of Tyke Tyler), in Richard Mabey's prescient classic The Unofficial Countryside and Kenneth Allsop's neglected classic Adventure Lit Their Star, and so on. So modish are the edgelands, indeed, that this summer there is a short-film festival dedicated to "liminal Britain" and "urban outskirts".

Iain Sinclair, too, has been prowling the edgelands for years – but he is anathema to Farley and Symmons Roberts because of his alleged "misanthropy". Much is also made of the misanthropy of "traditional" romantic celebrants of moor and mountaintop. The authors set themselves up – in opposition to both these modes – as social-minded saviours; their book a corrective in which they will "talk to edgelands people", and seek out the "voices of people who still carry the traces of local place in their mouths, in their tongues".

Sounds good. But their edgeland turns out to be a region almost as evacuated of its inhabitants as Sebald's Suffolk or Yves Marchand's Detroit. "Hundreds of conversations" are referred to in the acknowledgments, but a meagre half-dozen are (briefly) rehearsed in the book. A few individuals stumble past in the distance, like extras from The Road. When the inhabitants of this "loved and lived-in" landscape do appear centre-stage, they are left faceless, nameless and allegorical. Sometimes the edgelanders get laughed at. There is an uncomfortable joke about whether the medical condition of anosmia should be rechristened "binman's nose", and a receptionist in a pallet-yard is soundly patronised for not understanding their interest in pallets.

The book also suffers from an inverted form of the blitheness that can beset traditionally romantic nature writing. A pond on the outskirts of Peterborough is "a Pre-Raphaelite vision". Burnt-out cars dumped on waste ground "provide . . . a space where children can turn immobility into limitless freedoms". Waste ground is paradise. Sewage farms are "simple geometric playgrounds" where children have been known to ride the sweep-arms. "Container yards are places of beauty and mystery." Well, perhaps, but they are also places of crushed fingers and low wages. In the end, the love shown for the edgelands is too strong. There is at times an atmosphere of what Patrick Wright calls "the New Baroque sensibility", characterised by a romancing "interest in debris and human fall-out".

In the end, the thought-crimes of which Farley and Symmons Roberts accuse traditional landscape romantics (the editing out of particular people, the excesses of the lyric impulse) get re-performed almost perfectly here, just in a new setting. And there is nothing to suggest that Farley and Symmons Roberts would be anything other than pleased if the edgelands were to sprawl across the entirety of England. A strange book, then. Brilliant in parts, but confused in others. A book which, in its inconsistent, undecided texture is entirely in keeping with its subject.